On Tue, Mar 21, 2006 at 08:33:50PM +0000, Simon Riggs wrote: > On Tue, 2006-03-21 at 06:22 -0600, Jim C. Nasby wrote: > > Currently, it appears that SELECT * INTO new_table FROM old_table logs > > each page as it's written to WAL. Is this actually needed? Couldn't the > > database simply log that the SELECT ... INTO statement was executed > > instead? Doing so would likely result in a large performance improvement > > in most installs. Is there no provision for writing anything but data > > page changes (or whole pages) to WAL? > > AFAIK it takes the same code path as CREATE TABLE AS SELECT, which > already does exactly what you suggest (except when using PITR). Ok, I saw disk activity on the base directory and assumed it was pg_xlog stuff. Turns out that both SELECT INTO and CREATE TABLE AS ignore default_tablepsace and create the new tables in the base directory. I'm guessing that's a bug... (this is on 8.1.2, btw). Also, why do we log rows for CTAS/SELECT INTO when PITR is in use for simple SELECTs (ones that don't call non-deterministic functions)? The data should alread be available AFAICS... -- Jim C. Nasby, Sr. Engineering Consultant jnasby@xxxxxxxxxxxxx Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
